Image-forming device having holder unit, in which toner box is detachably mounted

ABSTRACT

An image forming device includes: a main casing; a holder unit; a plurality of image bearing members; a plurality of developing units; a plurality of toner boxes; and an operation assembly. The main casing defines an accommodation space. The holder unit is configured to be movable in a moving direction between an accommodated position in which the holder unit is accommodated in the accommodation space and a pull-out position in which at least part of the holder unit is outside of the accommodation space. The plurality of image bearing members are held by the holder unit and are juxtaposedly arrayed in the moving direction with intervals between neighboring image bearing members. The plurality of developing units are held by the holder unit in one to one correspondence with the plurality of image bearing members. The plurality of toner boxes are detachably attachable to the holder unit in one to one correspondence with the plurality of developing units. Each toner box is detachably attachable to the holder unit at the pull-out position. Each toner box includes: a toner container accommodating therein toner and formed with an opening through which toner in the toner container is to be supplied to each developing unit; and a shutter movable between an open position for opening the opening and a closed position for closing the opening. The operation assembly is provided at the holder unit and configured to move the shutter between the open position and the closed position.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from Japanese Patent Application No.2010-113666 filed May 17, 2010. The entire content of this priorityapplication is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to an image forming device such as a laserprinter.

BACKGROUND

According to a conventional tandem type color printer, fourphotosensitive drums for the colors of yellow magenta, cyan and blackcan be integrally attached to or detached from a main casing.

In such type of color printer, a frame can be pulled out in a horizontaldirection from the main casing, and four photosensitive drums are heldin the frame and arrayed in a pull-out direction of the frame. Further,developing cartridges provided with developing rollers and correspondingto these photosensitive drums are detachably mounted on the frame fromthe above. If toner in a developing cartridge gets empty, the developingcartridge is taken out of the frame, and a new developing cartridge ismounted on the frame.

SUMMARY

Recently, a low cost and environmentally preferable printer is required.To this effect, exchange in toner box only is preferable rather thanexchange in developer cartridge when the toner is used up. In theexchange in toner box only, only the toner box is exchanged with a newtoner box while a developing roller remains in the frame.

It is an object of the invention to provide an improved image-formingdevice, in which a holder unit is movably provided and a toner box isdetachably mounted in the holder unit.

In order to attain the above and other objects, the invention providesan image forming device including: a main casing; a holder unit; aplurality of image bearing members; a plurality of developing units; aplurality of toner boxes; and an operation assembly. The main casingdefines an accommodation space. The holder unit is configured to bemovable in a moving direction between an accommodated position in whichthe holder unit is accommodated in the accommodation space and apull-out position in which at least part of the holder unit is outsideof the accommodation space. The plurality of image bearing members areheld by the holder unit and are juxtaposedly arrayed in the movingdirection with intervals between neighboring image bearing members. Theplurality of developing units are held by the holder unit in one to onecorrespondence with the plurality of image bearing members. Theplurality of toner boxes are detachably attachable to the holder unit inone to one correspondence with the plurality of developing units. Eachtoner box is detachably attachable to the holder unit at the pull-outposition. Each toner box includes: a toner container accommodatingtherein toner and formed with an opening through which toner in thetoner container is to be supplied to each developing unit; and a shuttermovable between an open position for opening the opening and a closedposition for closing the opening. The operation assembly is provided atthe holder unit and configured to move the shutter between the openposition and the closed position.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a cross-sectional view of a color printer according to anembodiment of the present invention;

FIG. 2 is a perspective view of the color printer in FIG. 1 showing adrawer unit that has been pulled outward from a main frame of theprinter;

FIG. 3 is a perspective view of the drawer unit in FIG. 2 when tonerboxes have all been removed;

FIG. 4A is a right side view of the drawer unit in FIG. 2 when openingmembers are in a second position and shutters are in an open position;

FIG. 4B is a left side view of the drawer unit when closing members arein a third position and the shutters are in the open position;

FIG. 5A is a right side view of the drawer unit when the opening membersare in a first position and the shutters are in a closed position;

FIG. 5B is a left side view of the drawer unit when the closing membersare in a fourth position and the shutters are in the closed position;

FIG. 6 is a perspective view of a mechanism for interlocking the openingmember shown in FIG. 4A with the closing member shown in FIG. 4B;

FIG. 7 is a plan view of the drawer unit in FIG. 3;

FIG. 8 is a cross-sectional view of the drawer unit taken along thecross-sectional line VIII-VIII shown in FIG. 7;

FIG. 9 is a perspective view of a shutter drive member shown in FIG. 8;

FIG. 10 is a perspective view of a main body part of the shutter drivemember shown in FIG. 9;

FIG. 11 is a perspective view of one of the toner boxes shown in FIG. 1;

FIG. 12 is an exploded perspective view of the toner box in FIG. 11;

FIG. 13 is a side view of a toner seal shown in FIG. 12;

FIG. 14 is a partial perspective view of the surface of a mesh layershown in FIG. 13;

FIG. 15 is a cross-sectional view of the mesh layer;

FIG. 16A is a bottom view of the toner box in FIG. 11 when the shutteris in the open position;

FIG. 16B is a bottom view of the toner box when the shutter is in theclosed position;

FIG. 17A is a cross-sectional view of the toner box in FIG. 11 and theshutter drive member in FIG. 7 when the shutter is in the open position;

FIG. 17B is a cross-sectional view of the toner box in FIG. 11 and theshutter drive member in FIG. 7 when the shutter is in the closedposition;

FIG. 18A is a left side view of the toner box in FIG. 11 and the shutterdrive member in FIG. 7 showing the state of a locking mechanism beforethe toner box has been coupled with the shutter drive member;

FIG. 18B is a left side view of the toner box in FIG. 11 and the shutterdrive member in FIG. 7 showing the state of the locking mechanism afterthe toner box has been coupled with the shutter drive member;

FIG. 19 is a partial perspective view of the locking mechanism shown inFIGS. 18A and 18B;

FIG. 20A is a cross-sectional view of the shutter and locking mechanismwhen the shutter is fixed by the locking mechanism;

FIG. 20B is a cross-sectional view of the shutter and locking mechanismwhen the shutter is not fixed by the locking mechanism;

FIG. 21A is a perspective view of the opening member, closing member andtheir interlocking mechanism according to a first modification andshowing a state where the opening member is at a second position and theclosing member is at a third position;

FIG. 21B is a perspective view of the opening member, the closing memberand their interlocking mechanism according to the first modification andshowing a state where the opening member is at a first position and theclosing member is at a fourth position;

FIG. 22A is a perspective view of the opening member, closing member andtheir interlocking mechanism according to a second modification andshowing a state where the opening member is at a first position and theclosing member is at a fourth position;

FIG. 22B is a perspective view of the opening member, closing member andtheir interlocking mechanism according to the second modification andshowing a state where the opening member is at a second position and theclosing member is at a third position;

FIG. 23A is a perspective view of the opening member, closing member andtheir interlocking mechanism according to a third modification andshowing a state where the opening member is at a second position and theclosing member is at a third position; and

FIG. 23B is a perspective view of the opening member, closing member andtheir interlocking mechanism according to the third modification andshowing a state where the opening member is at a first position and theclosing member is at a fourth position.

DETAILED DESCRIPTION

Next, an embodiment of the present invention will be described whilereferring to the accompanying drawings.

1. Structure of a Color Printer

As shown in FIG. 1, the image-forming device according to the embodimentis a tandem-type color printer 1. As shown in FIGS. 1 and 2, the colorprinter 1 includes a main casing 2. A drawer unit 3 is mounted insidethe main casing 2. A front cover 4 is provided on the front surface ofthe main casing 2 and is capable of being opened and closed thereon.When the front cover 4 is open, the drawer unit 3 can be movedhorizontally between an accommodated position inside the main casing 2,as indicated by solid lines in FIG. 1, and a pull-out position outsidethe main casing 2, as depicted virtually by dotted lines in FIG. 1 andshown in FIG. 2. It is noted that when the drawer unit 3 is in thepull-out position, the drawer unit 3 protrudes outside the main casing 2through an opening of the main casing 2 opened by the front cover 4, butis still partly mounted in the main casing 2. That is, when the drawerunit 3 is in the pull-out position, the drawer unit 3 is not detachedfrom the main casing 2, but is still supported by the main casing 2. Forexample, a guide unit (not shown) is provided in the main casing 2 toguide the drawer unit 3 between the accommodated position and thepull-out position. The drawer unit 3 is slidably movable on the guideunit between the accommodated position and the pull-out position. So,even when the drawer unit 3 is in the pull-out position, the drawer unit3 is still partly on the guide unit, and is therefore not detached fromthe main casing 2. Thus, also in the pull-out position, the drawer unit3 is still mounted in the main casing 2, while partly protruding outsideof the main casing 2.

In the following description, the side of the color printer 1 on whichthe front cover 4 is provided (right side in FIG. 1) will be referred toas the front side of the color printer 1. The top, bottom, left, andright sides of the color printer 1 in the following description will bebased on the reference point of a user viewing the color printer 1 fromthe front side. Directions related to the drawer unit 3 and toner boxes11, described later, that are mounted in the drawer unit 3 will bereferenced based on their positions when mounted in the main casing 2,unless otherwise specified. Note that the front cover 4 has been omittedfrom FIG. 2.

As shown in FIG. 1, four photosensitive drums 5 (image-bearing members)are rotatably retained in the drawer unit 3. The photosensitive drums 5are capable of rotating about axes extending in the left-to-rightdirection. The four photosensitive drums 5 are respectively provided forthe colors black, yellow, magenta, and cyan. The photosensitive drums 5are arranged parallel to each other at regular intervals in thefront-to-rear direction in the order black, yellow, magenta, and cyan.

Four chargers 6 are also retained in the drawer unit 3. The chargers 6have a one-on-one correspondence to the four photosensitive drums 5 andare disposed at positions diagonally upward and rearward from thecorresponding photosensitive drums 5. Each charger 6 is a Scorotroncharger that includes a discharge wire and grid, for example.

Four developing units 7 are also retained in the drawer unit 3. The fourdeveloping units 7 also have a one-on-one correspondence to the fourphotosensitive drums 5 and are disposed diagonally above and forward ofthe corresponding photosensitive drums 5. Each developing unit 7includes a developing unit frame 8, and a developing roller 9accommodated in the developing unit frame 8. The developing roller 9 isdisposed in contact with the photosensitive drum 5 and is capable ofrotating about an axis extending in the left-to-right direction.

Four cleaners 10 are also retained in the drawer unit 3. The cleaners 10are provided with a one-on-one correspondence to the four photosensitivedrums 5 and are positioned rearward of the corresponding photosensitivedrums 5. The cleaners 10 function to move paper dust and the likedeposited on the surfaces of the photosensitive drums 5.

A space 12 is provided in the drawer unit 3 above each developing unit7. A toner box 11 that accommodates toner is mounted in the space 12formed above each developing unit 7. Sufficient room above the drawerunit 3 for mounting the toner boxes 11 in the spaces 12 is acquired bypulling the drawer unit 3 outward to the pull-out position. The tonerboxes 11 supply toner to the corresponding developing units 7.

An exposure device 13 is provided in the main casing 2 above the drawerunit 3. The exposure device 13 irradiates four laser beams correspondingto the four colors used by the color printer 1.

As each photosensitive drum 5 rotates, the corresponding charger 6applies a uniform charge to the surface of the photosensitive drum 5through corona discharge. Subsequently, the exposure device 13irradiates laser beams for selectively exposing the surfaces of thephotosensitive drums 5. This exposure selectively removes charge fromthe surfaces of the photosensitive drums 5, forming electrostatic latentimages thereon. When the electrostatic latent image carried on thesurface of a photosensitive drum 5 rotates to a position opposite thecorresponding developing roller 9, the developing roller 9 suppliestoner to the latent image, developing the image into a toner image. Thatis, the developing roller 9 executes a developing operation.

Here, four LED arrays may be provided for the four photosensitive drums5 in place of the exposure device 13.

A paper cassette 14 accommodating sheets of a paper P is disposed in abottom section of the main casing 2. The paper P accommodated in thepaper cassette 14 is conveyed onto a conveying belt 15 by variousrollers. The conveying belt 15 confronts the four photosensitive drums 5from below. Four transfer rollers 16 are disposed inside the conveyingbelt 15 at positions confronting each of the photosensitive drums 5through the upper portion of the conveying belt 15. When a sheet ofpaper P is conveyed onto the conveying belt 15, the conveying belt 15carries the sheet sequentially through positions between the conveyingbelt 15 and each of the photosensitive drums 5. As the sheet passesbeneath each photosensitive drum 5, the toner image carried on thesurface of the photosensitive drum 5 is transferred onto the paper P.

A fixing unit 17 is provided on the downstream end of the conveying belt15 with respect to the direction that the paper P is conveyed. Aftertoner images are transferred onto a sheet of paper P, the sheet isconveyed to the fixing unit 17, where the toner images are fixed to thesheet by heat and pressure. After the toner images are fixed in thefixing unit 17, various rollers discharge the sheet onto a dischargetray 18 formed on the top surface of the main casing 2.

2. Drawer Unit

(1) Drawer Frame

As shown in FIG. 3, the drawer unit 3 has a drawer frame 21 (holderunit). The drawer frame 21 is configured of a pair of side plates 22 and23 arranged parallel to each other and separated in the left-to-rightdirection, a front beam 24 bridging the front ends of the side plates 22and 23, and a rear beam 25 bridging the rear ends of the side plates 22and 23. The overall structure of the drawer frame 21 is square-shaped ina plan view.

The respective groups of four photosensitive drums 5, chargers 6,developing units 7, and cleaners 10 (see FIG. 1) are all held togetherbetween the side plates 22 and 23 on the left and right sides thereof.The spaces 12 in which the toner boxes 11 are mounted are formed betweenthe side plates 22 and 23 above the corresponding developing units 7. Inother words, the side plates 22 and 23 hold the photosensitive drums 5,chargers 6, developing units 7, and cleaners 10. Further, the sideplates 22 and 23 oppose each other in the left-to-right direction, withgaps formed therebetween to allocate the spaces 12 in which the tonerboxes 11 are mounted.

(2) Opening Members

As shown in FIGS. 4A and 5A, four opening members 26 (operationassemblies or operation members) are disposed on the right side surface(outer surface) of the right side plate 23 at positions corresponding tothe spaces 12. Each opening member 26 includes a rotating support part(fulcrum part) 27 configured of a shaft extending in the left-to-rightdirection, and a lever part 28 coupled to the rotating support part 27.

The rotating support part 27 is rotatably supported in the side plate23.

The lever part 28 is integrally configured of a coupling part 29 havinga circular shape in a side view, and an arm part 30 that has a narrowelongated plate shape extending forward from the coupling part 29, forexample. The lever part 28 is coupled to the rotating support part 27 byinserting the rotating support part 27 into the coupling part 29 so thatthe rotating support part 27 cannot rotate relative to the coupling part29.

By pivoting the opening member 26 with the rotating support part 27serving as the fulcrum, the opening member 26 can be shifted between afirst position in which the arm part 30 of the lever part 28 slopesdiagonally forward and downward, as shown in FIG. 5A, and a secondposition in which the arm part 30 extends horizontally, as shown in FIG.4A. Hence, the direction in which the opening member 26 moves from thefirst position to the second position (i.e., the rotating direction) isclockwise when viewing the opening member 26 from the right side.

A first cover 31 is disposed above the opening members 26 on the rightside surface of the right side plate 23 for covering all four openingmembers 26 in the second position. In a cross-sectional view, the firstcover 31 is L-shaped, extending rightward, then bending and extendingdownward. As shown in FIG. 4A, most of the upper half of the couplingpart 29 and most of the entire arm part 30 constituting the lever part28 are accommodated inside the first cover 31 (between the first cover31 and the side plate 23) when the opening member 26 is in the secondposition. The first cover 31 is integrally formed with the side plate23.

(3) Closing Members

As shown in FIGS. 4B and 5B, four closing members 32 (operationassemblies or operation members) are disposed on the left side surface(outer surface) of the left side plate 22 at positions corresponding tothe spaces 12. Each closing member 32 includes a rotating support part(fulcrum part) 33 configured of a shaft extending in the left-to-rightdirection, and a lever part 34 coupled to the rotating support part 33.

The rotating support part 33 is rotatably supported in the side plate22.

The lever part 34 is integrally configured of a coupling part 35 havinga circular shape in a side view, and an arm part 36 that has a narrowelongated plate shape extending forward from the coupling part 35, forexample. The lever part 34 is coupled to the rotating support part 33 byinserting the rotating support part 33 into the coupling part 35 so thatthe rotating support part 33 cannot rotate relative to the coupling part35.

By pivoting the closing member 32 with the rotating support part 33serving as the fulcrum, the closing member 32 can be shifted between athird position in which the arm part 36 of the lever part 34 slopesdiagonally forward and downward, as shown in FIG. 4B, and a fourthposition in which the arm part 36 extends horizontally, as shown in FIG.5B. Hence, the direction in which the closing member 32 moves from thethird position to the fourth position (i.e., the rotating direction) isopposite the direction in which the opening member 26 moves from thefirst position to the second position, i.e., counterclockwise whenviewing the closing member 32 from the left side.

A second cover 37 is disposed above the closing members 32 on the leftside surface of the left side plate 22 for covering all four closingmembers 32 in the fourth position. In a cross-sectional view, the secondcover 37 is L-shaped, extending leftward, then bending and extendingdownward. As shown in FIG. 5B, most of the upper half of the couplingpart 35 and most of the entire arm part 36 constituting the lever part34 are accommodated inside the second cover 37 (between the second cover37 and the side plate 22) when the closing member 32 is in the fourthposition. The second cover 37 is integrally formed with the side plate22.

(4) Lever Interlocking Mechanism

As shown in FIG. 6, the rotating support part 33 of the closing member32 penetrates the left side plate 22 (see FIG. 3) and extends betweenthe side plates 22 and 23 in the left-to-right direction. As shown inFIG. 7, a left pinion gear 38 is mounted on the left end of the rotatingsupport part 33 to the right (inside) of the side plate 22 and is notcapable of rotating relative to the rotating support part 33. A smallgap is formed between the left pinion gear 38 and side plate 22 so thatrotation of the left pinion gear 38 is not hindered. Similarly, a rightpinion gear 39 is mounted on the right end of the rotating support part33 to the left (inside) of the side plate 23 and is not capable ofrotating relative to the rotating support part 33. The right pinion gear39 is longer than the left pinion gear 38 in the left-to-rightdirection. A small gap is formed between the right pinion gear 39 andside plate 23 so that rotation of the right pinion gear 39 is nothindered.

The rotating support part 27 of each opening member 26 penetrates theright side plate 23 (see FIG. 3). As shown in FIG. 6, the left end ofthe rotating support part 27 opposes the right pinion gear 39 from theupper rear side. A pinion gear 40 is mounted on the left end of therotating support part 27 and is incapable of rotating relative to therotating support part 27. The pinion gear 40 is engaged with the rightpinion gear 39.

As shown in FIGS. 4A, 4B, and 6, the positions of the opening members 26and closing members 32 mounted on the drawer frame 21 are adjusted sothat the closing members 32 are in their third positions when theopening members 26 are in their second positions.

When a closing member 32 is moved from the third position to the fourthposition, the corresponding rotating support part 33, left pinion gear38, and right pinion gear 39 rotate counterclockwise when viewed fromthe left. The rotation of the right pinion gear 39 is transferred to thepinion gear 40, rotating the pinion gear 40 and the rotating supportpart 27 clockwise in a left side view. Through the rotation of therotating support part 27, the opening member 26 is moved from the secondposition to the first position.

Similarly, when an opening member 26 is moved from the first position tothe second position, the rotating support part 27 and pinion gear 40rotate counterclockwise in a left side view. The rotation of the piniongear 40 is transferred to the right pinion gear 39, rotating the rightpinion gear 39, rotating support part 33, and left pinion gear 38clockwise in a left side view. The rotation of the rotating support part33 moves the closing member 32 from the fourth position to the thirdposition.

Accordingly, the opening member 26 moves from the second position to thefirst position in association with movement of the closing member 32from the third position to the fourth position. Similarly, the closingmember 32 moves from the fourth position to the third position inassociation with movement of the opening member 26 from the firstposition to the second position.

(5) Developing Unit Frame

As shown in FIGS. 3 and 7, the developing unit frames 8 are disposed atregular intervals in the front-to-rear direction and span between theside plates 22 and 23. The developing unit frames 8 define the spaces 12provided for mounting the toner boxes 11.

As shown in FIG. 8, a developing chamber 41 is formed in each developingunit frame 8 for accommodating the developing roller 9. The side of thedeveloping chamber 41 opposing the corresponding photosensitive drum 5is open. The developing roller 9 is disposed in the bottom of thedeveloping chamber 41 near the open side thereof.

The developing unit frame 8 also has a plate-shaped partitioning wall 42positioned between the developing chamber 41 and the space 12. Thepartitioning wall 42 curves in an arc shape with its convex side facingthe developing chamber 41. The partitioning wall 42 partitions theinterior of the developing unit frame 8 into the developing chamber 41and the space 12 formed above the developing chamber 41. As shown inFIG. 3, three rectangular openings 43 are formed in the circumferentialcenter of the partitioning wall 42. The rectangular openings 43 areformed at positions opposing three main-body-side communicationthrough-holes 58 (described later with reference to FIG. 12) formed inthe toner box 11 when the toner box 11 is mounted in the space 12.

(6) Shutter Drive Member

As shown in FIGS. 7 and 8, a shutter drive member 44 is movably disposedabove the partitioning wall 42 for driving a shutter 73 described later.

As shown in FIG. 9, the shutter drive member 44 includes a main bodypart 111 (resin plate) formed of a resin, and a reinforcing plate 112(metal plate) formed of a thin metal plate that is affixed to the mainbody part 111.

As shown in FIG. 10, the main body part 111 is integrally configured offour plate-shaped parts 441, 442, 443, and 444 arranged at intervals inthe left-to-right direction; and a coupling part 445 having a bar shapethat extends in the left-to-right direction for coupling the front edgesof the plate-shaped parts 441-444. Each of the plate-shaped parts441-444 is formed of a plate curved in an arc, with the convex sidefacing the developing chamber 41. The curved arc of the plate-shapedpart substantially conforms to the shape of the partitioning wall 42.

The shutter drive member 44 is provided above the partitioning wall 42of each developing unit frame 8. For simplification, only the shutterdrive member 44 disposed above one partitioning wall 42 is shown inFIGS. 7 and 8.

As shown in FIG. 7, the plate-shaped part 444 on the left end confrontsthe top of the left pinion gear 38. A left rack gear 46 is formed on thebottom surface of the plate-shaped part 444 (the surface opposing theleft pinion gear 38) for engaging with the left pinion gear 38.

As shown in FIG. 7, the plate-shaped part 441 on the right end confrontsthe top of the right pinion gear 39. More specifically, the pinion gear40 is engaged in the right end portion of the right pinion gear 39, andthe right pinion gear 39 extends farther leftward than the pinion gear40, as shown in FIG. 6. The plate-shaped part 441 opposes from above theportion of the right pinion gear 39 extending leftward from the piniongear 40. A right rack gear 45 is formed on the bottom surface of theplate-shaped part 441 opposing the right pinion gear 39 and is engagedwith the right pinion gear 39.

When a user operates one of the opening members 26 or closing members 32to rotate the respective left pinion gear 38 or right pinion gear 39,the rotations of the left pinion gear 38 and right pinion gear 39 aretransferred to the left rack gear 46 and right rack gear 45. As aresult, the shutter drive member 44 moves between a position opposingthe rectangular openings 43 (the position shown in FIG. 7) and aposition forward of the rectangular openings 43. More specifically, whenone of the opening members 26 is moved from the first position to thesecond position, the corresponding shutter drive member 44 moves forwardfrom the position opposing the rectangular openings 43 along with therotations of the left pinion gear 38 and right pinion gear 39 and isplaced in a position not opposing the rectangular openings 43.

From this state, if the closing member 32 is moved from the thirdposition to the fourth position, the shutter drive member 44 movesrearward along with the rotations of the left pinion gear 38 and rightpinion gear 39 from the position not opposing the rectangular openings43 to the position opposing the rectangular openings 43.

Shutter drive protrusions 47 are formed on the top surfaces of theplate-shaped parts 441-444 at positions corresponding to shutter driveopenings 88 described later.

The reinforcing plate 112 covers the entire region of the main body part111, excluding the right edge of the plate-shaped part 441 and the leftedge of the plate-shaped part 444. Insertion through-holes 113 areformed in the reinforcing plate 112 at positions overlapping the shutterdrive protrusions 47. Each of the shutter drive protrusions 47 isinserted through a corresponding insertion through-hole 113 andprotrudes upward from the reinforcing plate 112.

By overlaying the reinforcing plate 112 on the main body part 111 inthis way, it is possible to ensure sufficient rigidity of the shutterdrive member 44 so that the shutter drive member 44 can move the shutter73 described later with reference to FIG. 12 with sufficient stability.

Further, by inserting the shutter drive protrusions 47 through theinsertion through-holes 113 in the reinforcing plate 112, the positionof the reinforcing plate 112 relative to the main body part 111 remainsfixed with the shutter drive protrusions 47 protruding from thereinforcing plate 112.

Since the three rectangular openings 43 formed in the partitioning wall42 are opened and closed by the reinforcing plate 112 moving inassociation with the shutter drive member 44, the reinforcing plate 112functions as a developing-device-side shutter for opening and closingthe rectangular openings 43.

3. Toner Box

(1) Main Body

As shown in FIGS. 11 and 12, the toner box 11 includes a main body ortoner container 51 for accommodating toner. The main body 51 is formedof a resin material in a substantially hollowed-out semicircular columnshape and is elongated in the left-to-right direction. Morespecifically, the main body 51 has an internal space for accommodatingtoner that is formed by: a rectangular top surface 52 elongated in theleft-to-right direction; an arcing surface 53 that is connected to thefront edge of the top surface 52 and that has a substantiallysemicircular arc shape in a cross section with the convex side facingdownward; a fixing surface 54 extending parallel to the top surface 52and protruding rearward from the rear edge of the arcing surface 53; arear surface 55 bridging the rear edge of the top surface 52 and therear edge of the fixing surface 54; a left side surface 56 bridging therespective left edges of the top surface 52, arcing surface 53, fixingsurface 54 and rear surface 55; and a right side surface 57 bridging therespective right edges of the top surface 52, arcing surface 53, fixingsurface 54, and rear surface 55.

As shown in FIG. 12, three main-body-side communication through-holes(openings) 58 are formed in the arcing surface 53 of the main body 51 atpositions slightly rearward of the lowest end thereof. Themain-body-side communication through-holes 58 are rectangular in shapeand elongated in the left-to-right direction and are spaced at intervalsin the left-to-right direction. The main-body-side communicationthrough-holes 58 provide communication between the interior and exteriorof the main body 51.

Narrow slit-shaped relief grooves 59 are also formed in the arcingsurface 53. The relief grooves 59 extend in the peripheral direction ofthe arcing surface 53 and are formed one on each of the left and rightsides of each main-body-side communication through-hole 58.

As shown in FIGS. 16A and 16B, a plurality of positioning protrusions 60is fanned on the front edge of the arcing surface 53. The positioningprotrusions 60 are spaced at intervals in the left-to-right direction.As shown in FIGS. 17A and 17B, each positioning protrusion 60 has a hookshape, extending forward, then bending and extending upward.

As shown in FIG. 12, recessions 61 and 62 are respectively formed in theleft and right ends of the main body 51 in the lowest portion of thearcing surface 53. The recession 61 on the left side is open in the leftside surface 56 of the main body 51, while the recession 62 on the rightside is open in the right side surface 57 of the main body 51.

The toner box 11 further includes toner seals 71 affixed to the arcingsurface 53 of the main body 51, a shutter cover 72 disposed so as tocover the arcing surface 53, and a shutter 73 disposed between thearcing surface 53 and shutter cover 72.

(2) Toner Seals

As shown in FIG. 12, one of the toner seals 71 is provided for eachmain-body-side communication through-hole 58. The toner seal 71 has asheet-like form and is formed with an opening or through-hole 74 at aposition corresponding to the main-body-side communication through-hole58. The area of the opening 74 is greater than the area of themain-body-side communication through-hole 58. Thus, the toner seals 71are fixed to the arcing surface 53 of the main body 51 so that theopenings 74 are aligned and in communication with the correspondingmain-body-side communication through-holes 58 and, hence, encircle themain-body-side communication through-holes 58.

As shown in FIG. 13, each toner seal 71 has a laminated structure(two-layer structure) configured of an elastic layer 75, and a meshlayer 76 disposed on one surface of the elastic layer 75.

The elastic layer 75 is formed of a resilient foam material, such as theproduct PORON® (trade name, registered trade mark) manufactured byRogers Inoac Corporation. The elastic layer 75 is formed much thickerthan the mesh layer 76. A fixing surface 77 constituting the surface ofthe elastic layer 75 opposite the mesh layer 76 is fixed to the arcingsurface 53 of the main body 51 with adhesive.

FIG. 14 shows a surface portion of the mesh layer 76, while FIG. 15shows a cross-sectional portion of the same. As shown in the drawings,the mesh layer 76 includes warp fibers 78 and weft fibers 79 interlacedin a plain weave (an alternating over and under pattern).

As shown in FIGS. 16A and 16B, the portion of the toner seal 71 disposedforward of the main-body-side communication through-hole 58 (on thefront end side of the arcing surface 53) has a width D1 along thecircumferential direction of the arcing surface 53. The portion of thetoner seal 71 disposed rearward of the main-body-side communicationthrough-hole 58 (on the rear end side of the arcing surface 53) has awidth D2 along the circumferential direction of the arcing surface 53.The width D1 is greater than the width D2.

(3) Shutter Cover

The shutter cover 72 is curved to conform to the arcing surface 53 ofthe main body 51. The shutter cover 72 is formed of a resin film. Theshutter cover 72 has a thickness greater than or equal to 0.03 mm andsmaller than or equal to 0.3 mm, and preferably greater than or equal to0.08 mm and smaller than or equal to 0.2 mm. The left-to-right dimensionof the shutter cover 72 is approximately equal to the same dimension ofthe arcing surface 53, so that the shutter cover 72 covers the arcingsurface 53 across substantially the entire width in the left-to-rightdirection.

As shown in FIG. 12, a plurality of positioning openings 80 is formed inthe front edge portion of the shutter cover 72 at intervals in theleft-to-right direction. As shown in FIGS. 17A and 17B, the positioningprotrusions 60 formed on the arcing surface 53 of the main body 51 areengaged in the positioning openings 80. More specifically, thepositioning openings 80 are formed in the front edge portion of theshutter cover 72 at positions in the left-to-right directioncorresponding to the positioning protrusions 60 and of a sufficient sizefor inserting the positioning protrusions 60. After the positioningprotrusions 60 are inserted into the corresponding positioning openings80, the top edges of the positioning openings 80 engage the positioningprotrusions 60.

The rear edge part of the shutter cover 72 is folded back to conform tothe fixing surface 54 of the main body 51. A plurality of screwinsertion through-holes 81 are formed in this rear edge portion of theshutter cover 72 at intervals in the left-to-right direction, as shownin FIG. 12. As shown in FIGS. 16A and 16B, the shutter cover 72 isattached to the main body 51 by engaging the positioning protrusions 60in the respective positioning openings 80, and by inserting screws 82through all of the screw insertion through-holes 81 and screwing thetips of the screws 82 into the fixing surface 54 of the main body 51.

As shown in FIGS. 11 and 12, cover-side communication through-holes 83are formed in the shutter cover 72 at positions corresponding to thetoner seals 71. Each of the cover-side communication through-holes 83has a rectangular shape and is elongated in the left-to-right direction.Further, the cover-side communication through-hole 83 has a greater openarea than the area of the main-body-side communication through-hole 58so as to expose the main-body-side communication through-hole 58 in itsentirety. The size of each cover-side communication through-hole 83 issuch that when the shutter 73 is in an open position (described later),as shown in FIG. 16A, a gap is formed between the rear edge of thecorresponding toner seal 71 and the rear edge of the cover-sidecommunication through-hole 83, gaps are formed between the left andright edges of the corresponding toner seal 71 and the left and rightedges of the cover-side communication through-hole 83, and the frontedge portion of the corresponding toner seal 71 is interposed betweenthe shutter cover 72 and the arcing surface 53 of the main body 51.Consequently, when the shutter 73 is in the open position, the shuttercover 72 does not cover the rear edge and both left and right edges ofthe toner seal 71, allowing these edges to protrude outward through thecover-side communication through-hole 83.

As shown in FIG. 12, slanted parts 84 having portions angled relative tothe circumferential direction of the shutter cover 72 are formed on theshutter cover 72 in both rear side corners of each cover-sidecommunication through-hole 83 as part of the peripheral edge of thecover-side communication through-hole 83. With the slanted parts 84, theleft-to-right width of each cover-side communication through-hole 83grows narrower toward the rear edge of the shutter cover 72.

The part of each slanted part 84 forming a peripheral edge portion ofeach cover-side communication through-hole 83 may extend in a straightline or follow a gentle curve, provided that the portion is slantedrelative to the circumferential direction of the shutter cover 72. Theseportions of the slanted parts 84 are shaped in a gentle curve in theexample of FIG. 12.

Guide slits 85 elongated in the front-to-rear direction (circumferentialdirection of the shutter cover 72) are formed in the shutter cover 72 atpositions corresponding to the relief grooves 59 formed in the main body51. The guide slits 85 have a front-to-rear length that is greater thanor equal to the front-to-rear length of the relief grooves 59. Theleft-to-right width of the guide slits 85 is also greater than or equalto the left-to-right width of the relief grooves 59. Each guide slit 85confronts the corresponding relief groove 59 in its entirety.

Locking member insertion through-holes 86 and 87 are also formed in theshutter cover 72 at positions corresponding to the recessions 61 and 62formed in the main body 51.

(4) Shutter

As shown in FIG. 12, the shutter 73 curves along the arcing surface 53of the main body 51. The shutter 73 is formed of a resin film having awidth in the left-to-right direction slightly smaller than theleft-to-right width of the shutter cover 72. The dimension of theshutter 73 along the circumferential direction of the arcing surface 53is greater than the same dimension of the toner seals 71 and is set suchthat the shutter 73 does not contact the fixing surface 54 and thepositioning protrusions 60 when moving between an open position and aclosed position described later.

Two shutter drive openings 88 separated by a prescribed interval in thecircumferential direction of the shutter 73 are formed in the shutter 73at positions opposing each relief groove 59 in the main body 51. Thedistance between the two shutter drive openings 88 at each position isset such that all shutter drive openings 88 confront a correspondingrelief groove 59 and confront and communicate with a corresponding guideslit 85 formed in the shutter cover 72, regardless of whether theshutter 73 is in the open position or the closed position.

V-shaped notches 89 are formed in the rear edge of the shutter 73 (theedge of the shatter 73 on the rear edge side of the arcing surface 53)at positions in the left-to-right direction corresponding to themain-body-side communication through-holes 58 formed in the main body51. The V-shaped notches 89 open toward the rear edge side of the arcingsurface 53. Forming the V-shaped notches 89 in this way, produces slopedparts 90 in the rear edge of the shutter 73 that are angled relative tothe circumferential direction of the shutter 73.

Locking openings 91 and 92 are also formed in the shutter 73 atpositions opposing the recessions 61 and 62 formed in the main body 51when the shutter 73 is in the closed position. Hence, when the shutter73 is in the closed position, the locking openings 91 and 92 confrontthe recessions 61 and 62, respectively, and also confront the respectivelocking member insertion through-holes 86 and 87 formed in the shuttercover 72. Accordingly, the recession 61 and locking member insertionthrough-hole 86 are in communication via the locking opening 91, and therecession 62 and locking member insertion through-hole 87 are incommunication via the locking opening 92.

The shutter 73 is interposed between the arcing surface 53 of the mainbody 51 and the shutter cover 72. While held between the arcing surface53 and shutter cover 72, the shutter 73 can move between an openposition and a closed position described next.

(5) Open Position of the Shutter

In the open position shown in FIG. 16A, the shutter 73 is positioned onthe front side of the cover-side communication through-holes 83 formedin the shutter cover 72. More specifically, when the shutter 73 is inthe open position, the rear edge of the shutter 73 is positioned fartherforward than the front edges of the cover-side communicationthrough-holes 83, and the rear edge portion of the shutter 73 isinterposed between the front edge portion of the toner seal 71 and theshutter cover 72. Therefore, each main-body-side communicationthrough-hole 58 formed in the main body 51 and the opening 74 formed inthe corresponding toner seal 71 are made open, while being incommunication with each other. This provides communication between theinterior and exterior of the main body 51. Further, since the rear edgeand both left and right edges of the toner seal 71 are exposed, theseedges protrude outward through the cover-side communication through-hole83.

(6) Closed Position of the Shutter

In the closed position shown in FIG. 16B, the shutter 73 is positionedfarther rearward than the open position. When the shutter 73 is in theclosed position, the rear edge of the shutter 73 is positioned slightlyrearward than the rear edges of the cover-side communicationthrough-holes 83. Accordingly, the shutter 73 opposes nearly the entirearea of the cover-side communication through-holes 83, excluding theregions opposite part of the V-shaped notches 89 formed in the shutter73. The toner seals 71 are entirely interposed between the shutter 73and the arcing surface 53 of the main body 51. As a result, the shutter73 covers the main-body-side communication through-holes 58 formed inthe main body 51 and the openings 74 formed in the toner seals 71 intheir entirety, blocking communication between the interior and exteriorof the main body 51.

4. Mounting the Toner Box

Each toner box 11 is mounted in or removed from the corresponding space12 formed above the partitioning wall 42 of the developing unit frame 8(see FIG. 7) when the corresponding shutter 73 is in the closedposition.

When a toner box 11 is not mounted in the corresponding space 12, theopening member 26 is in the first position shown in FIG. 5A and theclosing member 32 is in the fourth position shown in FIG. 5B. Thecorresponding shutter drive member 44 above the partitioning wall 42 ispositioned opposite the rectangular openings 43 formed in thepartitioning wall 42, as shown in FIGS. 7 and 8.

With the drawer unit 3 (drawer frame 21) pulled out of the main casing 2to the pull-out position (see FIG. 1), the toner box 11 is mounted intothe corresponding space 12 from above. More specifically, when thedrawer unit 3 is at the pull-out position, the spaces 12 and theoperation members (opening members 26 and closing members 32) for allthe four colors are located outside of the main casing 2. So, the tonerboxes 11 for all the four colors can be mounted to and detached from thedrawer unit 3. For each color, one of the opening member 26 or theclosing members 32 that protrudes downwardly from the correspondingcover 31 or 37 can be accessed and manipulated by the user. At thistime, the shutter drive protrusions 47 positioned closer to the frontside among the pairs of shutter drive protrusions 47 formed in theshutter drive member 44 protrude upward along a substantially verticaldirection, while the shutter drive protrusions 47 positioned closer tothe rear protrude in a direction angled upward and forward, as shown inFIG. 17B. When the toner box 11 is mounted in the space 12, each of theshutter drive protrusions 47 engages in a corresponding shutter driveopening 88 through the corresponding guide slit 85.

While the drawer unit 3 remains in the pull-out position, an operatornext moves the opening member 26 from the first position shown in FIG.5A to the second position shown in FIG. 4A, causing the shutter drivemember 44 to move from a position confronting the rectangular openings43 to a position not confronting the rectangular openings 43 (see FIG.17A). In association with the movement of the shutter drive member 44,the shutter 73 moves forward from the closed position to the openposition.

As shown in FIG. 8, annular frame seals 93 are disposed on top of thepartitioning wall 42 at positions corresponding to each of the tonerseals 71. That is, the annular frame seals 93 are disposed on a surfaceof the partitioning wall 42 confronting the corresponding space 12 atpositions corresponding to each of the toner seals 71. The annular frameseals 93 surround the periphery or perimeter of each rectangular opening43. When the shutter 73 is in the open position, the rear edge and bothleft and right edges of each toner seal 71 protrudes outward through thecorresponding cover-side communication through-hole 83. The protrudingportions of the toner seal 71 directly press against the correspondingframe seal 93, and portions of the frame seal 93 that do not contact thetoner seal 71 contact the shutter cover 72. Therefore, the opening 74formed in each toner seal 71 is in communication with the correspondingrectangular opening 43 through the opening region in the correspondingframe seal 93, while the toner seal 71 and frame seal 93 seal any gapsformed between the partitioning wall 42 and shutter cover 72.

After all toner boxes 11 have been mounted in the corresponding spaces12, all opening members 26 have been shifted from their first positionsto their second positions, and the shutters 73 of all toner boxes 11 arein their open positions, the toner boxes 11 supply toner to allcorresponding developing units 7. Subsequently, the operator pushes thedrawer unit 3 to the accommodated position within the main casing 2 andcloses the front cover 4 (see FIG. 1). At this time, the user can beginperforming image-forming operations with the color printer 1.

In order to remove a toner box 11 from the drawer unit 3, the operatoropens the front cover 4 and pulls the drawer unit 3 outward from theaccommodated position to the pull-out position. Next, the operatorshifts the closing member 32 for the desired toner box 11 from the thirdposition shown in FIG. 4B to the fourth position shown in FIG. 5B. Thismovement of the closing member 32 moves the shutter drive member 44 froma position not confronting the rectangular openings 43 to a positionconfronting the rectangular openings 43 (see FIG. 17B). In associationwith the movement of the shutter drive member 44, the shutter 73 movesrearward from the open position to the closed position.

Next, the operator removes the toner box 11 from the space 12. Since theshutter 73 is in the closed position at this time, there is no risk oftoner spilling out of the main body 51 when the toner box 11 is removed.

5. Locking Mechanism

Since the shutter drive protrusions 47 are not engaged in the shutterdrive openings 88 when the toner box 11 has been removed from the drawerunit 3, the shutter 73 can move freely relative to the main body 51 andshutter cover 72. Therefore, if the toner box 11 were jolted, shaken, orthe like, the shutter 73 could move out of the closed position.

In order to fix the shutter 73 in the closed position while the tonerbox 11 is removed from the drawer unit 3, the toner box 11 in theembodiment has a locking mechanism 101 provided in each of therecessions 61 and 62, as shown in FIGS. 18A and 18B. Since the lockingmechanism 101 disposed in the recession 61 and the locking mechanism 101disposed in the recession 62 have the same structure, except in mirrorimage, the locking mechanism 101 disposed in the recession 61 will beused below for a collective description of the locking mechanisms 101.

As shown in FIG. 19, the locking mechanism 101 includes an arm 102, anda locking protrusion 103 attached to the arm 102.

The arm 102 is configured of a flexible thin plate, such as a leafspring. The arm 102 has the shape of a crank. That is, beginning fromone end, the arm 102 extends downward within the recession 61, thenbends and extends leftward, and finally bends and extends downward. Morespecifically, as shown in FIGS. 18A and 18B, the arm 102 is integrallyformed of a fixing part 104 extending downward within the recession 61,a holding part 105 extending leftward from the bottom edge of the fixingpart 104, and a contact part 106 extending downward from the left edgeof the holding part 105. The fixing part 104 is fixed to theleftward-facing surface of the main body 51 inside the recession 61 by ascrew 107.

As shown in FIG. 19, the locking protrusion 103 has a flattened squarepillar shape and is fixed to the bottom surface of the holding part 105.When the shutter 73 is in the closed position, the locking protrusion103 on the bottom surface of the holding part 105 is disposed in aposition opposing the locking opening 91 formed in the shutter 73.

Accordingly, when the toner box 11 has been removed from the drawer unit3, the locking protrusions 103 of both locking mechanisms 101 arerespectively inserted into the locking openings 91 and 92 formed in theshutter 73, as shown in FIGS. 18A and 20A, thereby preventing theshutter 73 from moving out of the closed position. Accordingly, thelocking mechanisms 101 prevent the shutter 73 from moving out of theclosed position while the toner box 11 has been removed from the drawerunit 3.

When the toner box 11 is mounted in a corresponding space 12 provided inthe drawer unit 3, the bottom edge of the contact part 106 contacts thetop surface of the shutter drive member 44 (the top surface of theplate-shaped part 441 or 444) during the mounting operation, as shown inFIGS. 18B and 20B. Thus, as the toner box 11 is moved farther in themounting direction, the force of resistance received from the shutterdrive member 44 causes the holding part 105 of the arm 102 to deform,bending so that the left end of the holding part 105 rises upward.Consequently, the locking protrusions 103 are extracted from the lockingopenings 91 and 92. At this time, the shutter 73 can move freelyrelative to the main body 51 and shutter cover 72 and can move togetherwith the shutter drive member 44.

6. Operations

(1) According to the above described embodiment, the drawer unit 3(drawer frame 21) is movable between the accommodated position in themain body casing 2 and the pull-out position, in which the drawer unit 3is partly outside the main body casing 2, but is still partly mounted onthe main casing 2. The plurality of photosensitive drums 5 are held inthe drawer frame 21 and are spacedly arrayed side by side in thefrontward/rearward direction which is the moving direction of the drawerunit 3. Further, the plurality of developing units 7 each correspondingto each photosensitive drum 5 are also held in the drawer frame 21.Further, the plurality of toner boxes 11 is held in the drawer frame 21.Each toner box 11 is provided for each developing unit 7 and isdetachably attached to the drawer frame 21 positioned at the pull-outposition.

The toner box 11 includes the main body or toner container 51accommodating toner therein, and the toner container 51 is formed withthe openings (main-body-side communication through-holes) 58 forsupplying toner to the developing unit 7. Further, the toner box 11 isprovided with the shutter 73 movable between open position and closedposition for opening and closing the openings 58.

The drawer frame 21 is provided with the opening member 26 and theclosing member 32 to be operated for moving the shutter 73 between itsopen position and closed position. The opening member 26 and the closingmember 32 are not provided at a position above each toner box 11, butare positioned at the drawer frame 21. Therefore, the opening member 26and the closing member 32 can be manipulated for moving the shutter 73at a position close to the center of gravity of the color printer 1,when the drawer unit 3 is at the pull-out position. Thus, overturning ofthe color printer 1 during manipulation to the opening member 26 and theclosing member 32 can be prevented.

Now assume a comparative example where the closing members and theopening members are provided in upper portions of the toner box. In sucha comparative example, the color printer will possibly be overturned.That is, after the drawer unit is pulled out from the main casing, acenter of gravity of the color printer is displaced toward the pull-outside of the drawer unit. In this state, the operation to the closingmembers and opening members will possibly impart a force on the drawerunit, thereby generating rotational moment to the printer. Contrarily,according to the present embodiment, the closing members and the openingmembers are provided to the drawer unit. So, the closing members andopening members can be manipulated at positions closer to the center ofgravity of the color printer 1, compared to the case where the closingmembers and opening members are provided in the upper portions of thetoner boxes.

(2) Further, the opening member 26 and the closing member 32 areseparating components from each other, and therefore, a degree offreedom for the design of the opening member 26 and closing member 32can be increased in comparison with a case where a single or commonoperation member performs movement of the shutter 73 between the openingand closing positions. Consequently, more accurate attention can bedrawn to the design of the opening member 26 and the closing member 32so as to further avoid load application that causes overturning of thecolor printer 1 during manipulation to the opening member 26 and closingmember 32. As a result, overturning of the color printer 1 can furtherbe prevented.

(3) The opening member 26 is moved upward from its first position to thesecond position for moving the shutter 73 from its closed position tothe open position. Further, the closing member 32 is moved upward fromits third position to the fourth position for moving the shutter 73 fromits open position to the closed position. The upward movement of theoperation members 26, 32 does not apply downward load to the drawerframe 21. Prevention of the overturning of the color printer 1 isattributed to the provision of the operation members 26, 32 to thedrawer frame 21.

(4) The drawer frame 21 includes the pair of side plates 22, 23extending in the moving direction thereof. The pair of side plates 22,23 are spaced away from each other so as to provide the space 12 for theaccommodation of the toner box 11. The opening member 26 and closingmember 32 are positioned externally of the side plates 22, 23, i.e.,opposite to the space 12 with respect to the side plates 22, 23, therebyimproving operability to these operation members.

(5) More specifically, the opening member 26 is positioned at the outerside of the right side plate 22, and the closing member 32 is positionedat the outer side of the left side plate 23. Therefore, the openingmember 26 and closing member 32 can be easily distinguished from eachother because of their layout. Thus, operability to these operationmembers can further be enhanced.

(6) The drawer unit 3 is provided with the shutter drive member 44 thatis connectable with the shutter 73 to move the shutter 73 between theopen position and the closed position. The shutter drive member 44 isconnected to the operation members 26, 32. Thus, the shutter drivingmember 44 can be moved upon operation of the operation members 26, 32,to thereby move the shutter 73 between the open position and closedposition. More specifically, each developing unit 7 is provided with theshutter driving member 44 for moving the shutter 73 between the openposition and the closed position. Each shutter driving member 44 extendsin the confronting direction of the pair of side plates 22, 23, and hasone end portion connected with the opening member 26 and other endportion connected with the closing member 32. Thus, the shutter drivingmember 44 can be moved upon operation of the opening member 26 andclosing member 32 to move the shutter 73 between the open position andclosed position.

(7) The opening member 26 and closing member 32 are pivotally movable.Thus, the opening member 26 can be moved from the first position to thesecond position by its pivotal motion, and the closing member 32 can bemoved from the third position to the fourth position by its pivotalmotion.

(8) Pivotally moving direction of the opening member 26 from the firstposition to the second position is opposite to pivotally movingdirection of the closing member 32 from the third position to the fourthposition when viewing the operation members 26, 32 from each externalside of each of the opening member 26 and the closing member 32. Inother words, pivotally moving direction of the opening member 26 fromthe first position to the second position is coincident with thepivotally moving direction of the closing member 32 from the thirdposition to the fourth position when viewing these operation members 26,32 from one fixed external side of one of the opening member 26 and theclosing member 32. Therefore, the shutter 73 can be moved from theclosed position to the open position and from the open position to theclosed position by pivotally moving the operation members 26, 32 in thesame direction.

(9) Each of the opening member 26 and closing member 32 has the rotatingsupport part 27, 33 and the lever part 28, 34 extending from therotating support part frontward (in the direction from the accommodatedposition to the pull-out position). Because each lever part 28, 34 ispositioned frontward of the rotating support part 27, 33, i.e., at thenear side when the drawer unit 3 is to be pulled out. Therefore, theselever parts 28, 34 are easily accessible to enhance operability to theselever parts.

(10) The lever part 28 of the opening member 26 and the lever part 34 ofthe closing member 32 extend in the horizontal direction when these arepositioned at the second position and fourth position, respectively.That is, the lever part 28 of the opening member 26 extends horizontallywhen the shutter 73 is open, and the lever part 34 of the closing member32 extends horizontally when the shutter 73 is closed. Therefore, openposition and closed position of the shutter 73 can be easily recognizedby the posture of these lever parts 28, 34.

(11) Further, the first cover 31 and second cover 37 are provided forcovering the opening member 26 at its second position and the closingmember 32 at its fourth position, respectively. Therefore, access tothese operation members 26, 32 at their second and fourth positions,respectively can be prevented.

Incidentally, the first cover 31 and the second cover 37 need not bepositioned above the operation members 26, 32, but can be positionedspaced away from the side plates 22, 23 of the drawer frame 21interposing the opening member 26 between the side plate 23 and thefirst cover 31, and interposing the closing member 32 between the sideplate 22 and the second cover 37. In the latter case, a gap between theside plate 23 and the first cover 31 and a gap between the side plate 22and the second cover 37 must be a size that prohibits access to theoperation members 26, 32 at their second and fourth positions.

(12) Further, four opening members 26 are collectively covered by thesingle first cover 31, and four closing members 32 are collectivelycovered by the single second cover 37, thereby reducing the numbers ofparts and components in comparison with a case where each opening member26 and each closing member 32 is covered by each cover. Thus, simplifiedand low cost device can be provided.

(13) The closing member 32 is moved from the fourth position to thethird position in interlocking relation to the movement of the openingmember 26 from the first position to the second position. Further, theopening member 26 is moved from the second position to the firstposition in interlocking relation to the movement of the closing member32 from the third position to the fourth position. Therefore, it isensured that the opening member 26 is positioned at the first positionwhen the shutter 73 is to be moved from the closed position to the openposition, and that the closing member 32 is positioned at the thirdposition when the shutter 73 is to be moved from the open position tothe closed position. Accordingly, enhanced operability to the openingmember 26 and closing member 32 can be provided.

7. Modifications

Various modifications are conceivable with respect to the opening member26, closing member 32 and the interlocking mechanism other than thestructure shown in FIG. 6.

(1) First Modification

As shown in FIGS. 21A and 21B, the rotating support part of the openingmember 26 can be commonly used for the rotating support part of theclosing member 32. That is, the rotating support part 33 can be used asrotating support parts for both of the operation members 26 and 32. Inother words, both of the lever parts 28 and 34 are coupled to therotating support part 33. The gear 40 and the rotating support part 27are omitted. In this case, the opening member 26 is coupled to therotating support part 33 such that the lever part 28 extends rearward.Further, the aim part 30 is oriented diagonally downward when theopening member 26 is at the first position shown in FIG. 21B, and isoriented horizontally when the opening member 26 is at the secondposition shown in FIG. 21A. On the other hand, the closing member 32 iscoupled to the rotating support part 33 such that the lever part 34extends frontward. Further, the arm part 36 is oriented horizontallywhen the closing member 32 is at the fourth position shown in FIG. 21B,and is oriented diagonally downward when the closing member 32 is at thethird position shown in FIG. 21A.

With this structure, pivotally moving direction of the opening member 26from the first position to the second position (counterclockwisedirection) is identical to pivotally moving direction of the closingmember 32 from the third position to the fourth position(counterclockwise direction) when viewing the operation members 26, 32from each external side of each of the opening member 26 and the closingmember 32. In other words, pivotally moving direction of the openingmember 26 from the first position to the second position is opposite tothe pivotally moving direction of the closing member 32 from the thirdposition to the fourth position when viewing these operation members 26,32 from one fixed external side of one of the opening member 26 and theclosing member 32. Therefore, the shutter 73 can be moved from theclosed position to the open position and from the open position to theclosed position by pivotally moving the operation members 26, 32 inopposite directions.

In addition, upward direction is realized when moving the opening member26 from the first position to the second position and moving the closingmember 32 from the third position to the fourth position. The upwardmovement of the operation members can avoid application of downward loadto the drawer unit 3, thereby preventing overturning of the colorprinter 1.

(2) Second Modification

The second modification shown in FIGS. 22A and 22B is similar to thefirst modification in that the opening member 26 and closing member 32are coupled to the common rotating support part 33. However, in thismodification, the closing member 32 is coupled to the rotating supportpart 33 such that the lever part 34 extends rearward. The arm part 36 ofthe closing member 32 is oriented diagonally downward at its thirdposition shown in FIG. 22B, and oriented horizontally at its fourthposition shown in FIG. 22A. On the other hand, the opening member 26 iscoupled to the rotating support part 33 such that the lever part 28extends frontward. The arm part 30 of the opening member 26 is orientedhorizontally at its second position shown in FIG. 22B, and orienteddiagonally downward at its first position shown in FIG. 22A.

With this structure, similarly to the first modification, pivotallymoving direction of the opening member 26 from the first position to thesecond position (clockwise direction) is identical to pivotally movingdirection of the closing member 32 from the third position to the fourthposition (clockwise direction) when viewing the operation members 26, 32from each external side of each of the opening member 26 and the closingmember 32. In other words, pivotally moving direction of the openingmember 26 from the first position to the second position is opposite tothe pivotally moving direction of the closing member 32 from the thirdposition to the fourth position when viewing these operation members 26,32 from one fixed external side of one of the opening member 26 and theclosing member 32. Therefore, the shutter 73 can be moved from theclosed position to the open position and from the open position to theclosed position by pivotally moving the operation members 26, 32 inopposite directions.

In addition, upward direction is realized when moving the opening member26 from the first position to the second position and moving the closingmember 32 from the third position to the fourth position. The upwardmovement of the operation members can avoid application of downward loadto the drawer unit 3, thereby preventing overturning of the colorprinter 1.

(3) Third Modification

In the above-described embodiment, four opening members 26 and fourclosing members 32 are provided at the drawer unit 3. Instead, accordingto the third modification, a single opening member 26 and a singleclosing member 32 are provided at front end portions of the side plates23, 22, respectively.

In this case, an interlocking mechanism shown in FIGS. 23A and 23B isprovided for interlockingly moving four shutter drive members 44 (FIG.10) by the operation of the single opening member 26 or the singleclosing member 32.

More specifically, lever parts 28 and 34 to be in the respective spaces12 in the above-described embodiment are dispensed with regarding thesecond to fourth mechanisms except for the frontmost mechanism. A rackgear 111 extends in the frontward/rearward direction and is positionedabove the pinion gears 40. The rack gear 111 has a lower surfaceprovided with gear teeth meshedly engaged each pinion gear 40. The rackgear 111 is movable in the frontward/rearward direction.

Upon moving the closing member 32 from the third position (FIG. 23A) tothe fourth position (FIG. 23B), the rotating support part 33, the leftpinion gear 38 and the right pinion gear 39 are rotated about their axesin the counterclockwise direction as viewed from the left side.Therefore, the frontmost pinion gear 40 meshed with the right piniongear 39 and the rotating support part 27 are rotated about their axes inthe clockwise direction as viewed from the left side. Accordingly, theopening member 26 is moved from the second position (FIG. 23A) to thefirst position (FIG. 23B). Further, the rack gear 111 is moved frontwardby the clockwise rotation of the frontmost pinion gear 40, so thatremaining three pinion gears 40 are also rotated in the clockwisedirection to rotate the three right pinion gears 39 and the three leftpinion gears 38 in the counterclockwise direction. Consequently, fourshutter drive members 44 are moved concurrently from the non-confrontingposition offset from the openings 43 to the rearward confrontingposition confronting the openings 43.

Upon moving the opening member 26 from the first position (FIG. 23B) tothe second position (FIG. 23A), the rotating support part 27 and thepinion gear 40 coupled to the opening member 26 are rotated in thecounterclockwise direction as viewed from the left side. Therefore, thefrontmost right pinion gear 39 meshedly engaged with the frontmostpinion gear 40, the rotating support part 33 and the left pinion gear 38are rotated in the clockwise direction as viewed from the left side.Accordingly, the closing member 32 is moved from the fourth position(FIG. 23B) to the third position (FIG. 23A). Further, the rack gear 111is moved rearward by the counterclockwise rotation of the frontmostpinion gear 40, so that remaining three pinion gears 40 are also rotatedin the counterclockwise direction to rotate the three right pinion gears39 and the three left pinion gears 38 in the clockwise direction.Consequently, four shutter drive members 44 are moved concurrently fromthe confronting position confronting the openings 43 to the nonconfronting position offset from the openings 43.

With this structure, all shutters 73 (FIG. 17A, 17B) can be concurrentlymoved between the open positions and the closed positions by way of theoperation to the single opening member 26 and the single closing member32. Thus, enhanced operability can result.

(4) Fourth Modification

In the above-described embodiment, the single first cover 31 covers thefour opening members 26 as shown in FIG. 4A, and the single second cover37 covers the four closing members 32 as shown in FIG. 4B. However, inthe fourth modification, four covers are provided for respectivelycovering four opening members 26 instead of the single first cover 31,and another four covers are provided for respectively covering fourclosing members 32 instead of the single second cover 37.

While the invention has been described in detail with reference to theembodiment and modifications thereof, it would be apparent to thoseskilled in the art that various changes and modifications may be madetherein without departing from the spirit of the invention.

1. An image forming device comprising: a main casing defining anaccommodation space; a holder unit configured to be movable in a movingdirection between an accommodated position in which the holder unit isaccommodated in the accommodation space and a pull-out position in whichat least part of the holder unit is outside of the accommodation space,a plurality of image bearing members that are held by the holder unitand that are juxtaposedly arrayed in the moving direction with intervalsbetween neighboring image bearing members; a plurality of developingunits that are held by the holder unit in one to one correspondence withthe plurality of image bearing members; a plurality of toner boxes thatare detachably attachable to the holder unit in one to onecorrespondence with the plurality of developing units, each toner boxbeing detachably attachable to the holder unit at the pull-out position,each toner box including: a toner container accommodating therein tonerand formed with an opening through which toner in the toner container isto be supplied to each developing unit; and a shutter movable between anopen position for opening the opening and a closed position for closingthe opening; and an operation assembly provided at the holder unit andconfigured to move the shutter between the open position and the closedposition.
 2. The image forming device as claimed in claim 1, wherein theoperation assembly comprises: a first operation assembly movable betweena first position and a second position and operable to be moved from thefirst position to the second position to move the shutter from theclosed position to the open position; and a second operation assemblymovable between a third position and a fourth position and operable tobe moved from the third position to the fourth position to move theshutter from the open position to the closed position.
 3. The imageforming device as claimed in claim 2, wherein the operation assembly isconfigured to provide upward movement of at least part of the firstoperation assembly when the first operation assembly is moved from thefirst position to the second position and to provide upward movement ofat least part of the second operation assembly when the second operationassembly is moved from the third position to the fourth position.
 4. Theimage forming device as claimed in claim 3, wherein the holder unitcomprises a pair of side plates extending in the moving direction andspaced away from each other to provide a space therebetween foraccommodation of the toner box, the first operation assembly and thesecond operation assembly being positioned at outer sides of the pair ofside plates opposite to the space.
 5. The image forming device asclaimed in claim 4, wherein the first operation assembly is provided atone of the side plates at a position opposite to the space with respectto the one of the side plates, and the second operation assembly isprovided at remaining one of the side plates at a position opposite tothe space with respect to the remaining one of the side plates.
 6. Theimage forming device as claimed in claim 5, wherein the pair of sideplates confront with each other in a confronting direction; and whereinthe developing unit includes a shutter drive member that extends in theconfronting direction and that is connectable with the shutter to movethe shutter between the open position and the closed position, theshutter drive member having one end portion connected to the firstoperation assembly, and another end portion connected to the secondoperation assembly.
 7. The image forming device as claimed in claim 5,wherein the first operation assembly and the second operation assemblyare pivotally movable with respect to the side plates.
 8. The imageforming device as claimed in claim 7, wherein the first operationassembly is configured to provide a first pivoting direction as viewedfrom an outer side thereof opposite to the space when the firstoperation assembly moves from the first position to the second position,and the second operation assembly is configured to provide a secondpivoting direction opposite to the first pivoting direction as viewedfrom an outer side of the second operation assembly opposite to thespace when the second operation assembly moves from the third positionto the fourth position.
 9. The image forming device as claimed in claim8, wherein the first operation assembly comprises a first rotatingsupport part and a first lever part extending from the first rotatingsupport part in a direction from the accommodated position toward thepull-put position, and the second operation assembly comprises a secondrotating support part and a second lever part extending from the secondrotating support part in a direction from the accommodated position tothe pull-put position.
 10. The image forming device as claimed in claim7, wherein the first operation assembly is configured to provide apivoting direction as viewed from an outer side thereof opposite to thespace when the first operation assembly moves from the first position tothe second position, and the second operation assembly is configured toprovide a pivoting direction identical to the pivoting direction of thefirst operation assembly as viewed from an outer side of the secondoperation assembly opposite to the space when the second operationassembly moves from the third position to the fourth position.
 11. Theimage forming device as claimed in claim 10, wherein the first operationassembly comprises a rotating support part and a first lever partextending from the rotating support part in a direction from theaccommodated position toward the pull-out position, and the secondoperation assembly comprises the rotating support part and a secondlever part extending from the rotating support part in a direction fromthe pull-out position to the accommodated position.
 12. The imageforming device as claimed in claim 10 wherein the first operationassembly comprises a rotating support part and a first lever partextending from the rotating support part in a direction from thepull-out position to the accommodated position, and the second operationassembly comprises the rotating support part and a second lever partextending from the rotating support part in a direction from theaccommodated position to the pull-out position.
 13. The image formingdevice as claimed in claim 9, wherein the first lever part of the firstoperation assembly extends horizontally at the second position, and thesecond lever part of the second operation assembly extends horizontallyat the fourth position.
 14. The image forming device as claimed in claim2, further comprising a cover configured to cover the first operationassembly at the second position and the second operation assembly at thefourth position.
 15. The image forming device as claimed in claim 14,wherein the first operation assembly comprises a plurality of firstassemblies each provided for each toner box, and the second operationassembly comprises a plurality of second assemblies each provided foreach toner box, and, wherein the cover comprises a first covercollectively covering the plurality of first assemblies, and a secondcover collectively covering the plurality of second assemblies.
 16. Theimage forming device as claimed in claim 14, wherein the cover ispositioned above the first operation assembly and the second operationassembly.
 17. The image forming device as claimed in claim 2, whereinthe first operation assembly comprises a single first assembly for theplurality of toner boxes, and the second operation assembly comprises asingle second assembly for the plurality of toner boxes, and, the imageforming device further comprising an interlocking mechanism configuredto interlockingly move the plurality of shutters of the plurality oftoner boxes from closed positions to the open positions in accordancewith the movement of the first assembly from the first position to thesecond position, and to interlockingly move the plurality of shutters ofthe plurality of toner boxes from open position to the closed positionin accordance with the movement of the second assembly from the thirdposition to the fourth position.
 18. The image forming device as claimedin claim 2, wherein the first operation assembly is configured to movefrom the second position to the first position in interlocking relationto the movement of the second operation assembly from the third positionto the fourth position, and the second operation assembly is configuredto move from the fourth position to the third position in interlockingrelation to the movement of the first operation assembly from the firstposition to the second position.
 19. The image forming device as claimedin claim 1, wherein the holder unit includes a shutter drive member thatis connected to the operation assembly and that is configured so as tobe connectable with the shutter to move the shutter between the openposition and the closed position.